A Delhi court warned former corporate lobbyist Niira Radia for "evading" questions relating to the 2G spectrum allocation case in which she is considered a "sensitive" witness.

"Be brief and specific in your answers," special CBI Judge OP Saini told her when she was speaking in an inaudible manner.

Fifty three-year-old Radia, who appeared for the first time in the case as a CBI witness, said she had been advising the Tatas on telecom issues and the Tata Teleservices Ltd (TTSL) had opposed the allocation of spectrum to Swan Telecom Pvt Ltd (STPL) and Reliance Communications Ltd.

Radia evaded a question by the CBI prosecutor as to why TTSL was granted CDMA licence in 2008, three years after it had applied in 2005.

She then said that TTSL, which was ahead in the queue for allocation of spectrum, lost the race while an "ineligible" STPL owned by ADAG Reliance Communications was granted the radiowaves.